Blanking presses for cutting blanks from sheet material are well known, and in some such presses, such as shown in U.S. Pat. No. 3,776,017 and Japanese Published Application No. 60-20335, pushers are provided to push the cut blanks out of the press laterally of the direction in which the strip material from which the blanks are cut is fed to the press. In order to make it possible to cut various shapes of blanks from a strip of sheet material, such a press has been developed which has adjustable shear blades.
One such blanking press is shown in Japanese Published Application No. 60-176837, published Nov. 22, 1985, in which there is provided a single shear blade means which can be pivoted from a position transverse to the path of a strip of sheet material in opposite directions so as to cut either rectangular blanks from the end of the strip or trapezoidal blanks from the end of the strip.
An improved version of such a press is also known, as shown in FIGS. 1 and 2, in which the press is provided with a pair of adjustable shear blade means 15, which extend transversely of the path of a sheet of material 10, such as sheet metal, fed from a roll 11 of such material through a leveler 12 to the press 13. The adjustable shear blade means 15 extends generally transversely of the direction of travel of the strip 10 of sheet material, and can be moved closer together or farther apart relative to each other, and can be pivoted freely from positions which are transverse to the direction of travel of the sheet to positions which are at an angle to the direction of travel of the sheet. Thus, with the adjustable shear blade means 15 extending transversely across the sheet at angles to the direction of travel of the sheet, with the one ends on one side closer together than the ends on the other side, as shown in FIG. 1, two equilaterial trapezoidal blanks A and B can be cut from the end of the strip at each operation of the press. If the blanks cut from the sheet in a preceding step are equilaterally shaped trapezoids, then the blank B at the extreme end of the strip can be made the same shape, but oriented 180.degree. to blank A, and the blank A will be a similarly shaped trapezoidal sheet with the same orientation as the blank which has been last cut from the strip.
Alternatively, by adjusting the position of one or the other of the adjustable shear blade means 15 so that it is perpendicular to the direction of travel of the strip, while leaving the other of the adjustable shear blade means 15 at an angle, irregular trapezoidal shapes, such as the shapes C and D in FIG. 3 can be cut from the end of the strip. By further adjusting the other adjustable shear blade means 15 so that it too is perpendicular to the direction of travel, rectangular shapes such as shapes E and F can be cut from the end of the strip. By adjusting the distance between the shear blade means 15, i.e. by moving one or the other, or both, the blanks can be made shorter or longer.
Thus, for any such shapes, two similarly shaped blanks can be cut from the end of the strip at the same time rather than just one as with the above-described press. In conjunction with the press 13 there is provided a longitudinal conveyor 17, shown at the right end of the press in FIGS. 1 and 2, which conveys the blank B cut from the end of the strip in the direction of travel of the strip to a stack 18 of cut blanks.
However, the blank A which is cut from between the adjustable shear blade means 15 must be moved laterally of the direction of conveyance of the strip 10, and for this purpose, a pusher 16 is provided along the edge of the conveyor between the one ends of the shear blade means, which, after the blank A has been cut from between the adjustable shear blade means 15, is actuated to push the blank A laterally of the direction of conveyance onto a lateral conveyor 19, which delivers the blank to a stack 20 of such blanks.
It is necessary, regardless of the shape of the blanks, that for good lateral conveyance of the blank A cut from between the adjustable shear blade means 15 that the pusher 16 engage the edge of the blank A midway between the one ends of the adjustable shear blade means 15.
In currently used presses of this type, when the positions of the adjustable shear blade means 15 are changed, the pusher 16 is manually shifted so that it is positioned midway between the one ends of the adjustable shear blade means positioned in their new positions. Such adjustment of the position of the pusher is done manually by an operator, and, while this can sometimes be accomplished during the time it takes to shift the positions of the adjustable shear blade means, it is frequently required to readjust the position of the pusher to get it in the exact location. This takes additional time and effort, which delays the startup of the means for feeding the strip of sheet material, and also requires the presence of an operator to make the adjustment.